100 This is the most serious problem of our time. We are firmly convinced that the basic propositions of atheism are utterly false and irreconcilable with the underlying principles of thought. They strike at the genuine and effective foundation for man's acceptance of a rational order in the universe, and introduce into human life a futile kind of dogmatism which far from solving life's difficulties, only degrades it and saddens it. Any social system based on these principles is doomed to utter destruction. Atheism, therefore, is not a liberating force, but a catastrophic one, for it seeks to quench the light of the living God. We shall therefore resist this growing evil with all our strength, spurred on by our great zeal for safeguarding the truth, inspired by our social duty of loyally professing Christ and His gospel, and driven on by a burning, unquenchable love, which makes man's good our constant concern. We shall resist in the invincible hope that modern man may recognize the religious ideals which the Catholic faith sets before him and feel himself drawn to seek a form of civilization which will never fail him but will lead on to the natural and supernatural perfection of the human spirit. May the grace of God enable him to possess his temporal goods in peace and honor and to live in the assurance of acquiring those that are eternal.
Source: Ecclesiam Suam (Vatican.va)